You might not be doing anything wrong, but the way to know for sure is to try it on a food dislike first. That's a good test of your technique, because if you can't get rid of a food dislike with it, it is indeed your technique that's wrong.

If you've succeeded with a food dislike, but are having trouble with something else, it's much less likely your technique, and more likely that you have something the method doesn't work on. (Or that you haven't fully surfaced the emotional threat, i.e., haven't asked "what's bad about that?" enough to get to a strong feeling.)